It is used on KineMOUNT, for Kine cameras. Kine cameras turn into camera which can use EF or EF-S lens in one second.
WHOLE NEW LOCK-TYPE EF MOUNT. From 2014 Jan, every mounting adapter employs whole new lock-type mount. Its fixing way is very similar to Cine PL mount: lock ring rotation, not lens rotation to make sure lens locked firmly in any case. Compared to traditional lock way based on metal spring, the new EF mount gains much better stability; fits very well in professional way when video shots using follow-focus gear.
It supports majority of lens with iris-control: Kine camera displays Iris number and tune it directly. Also you can just disable electronic active EF mounting adapter so that protects it from all-metal lens backend.